Vehicle clutch driven plate assemblies often utilize vibration damping means in the friction clutch structure for a manually actuated transmission to overcome objectionable vibration and rattle. Such vibration and rattle generally occur during the torsional engagement of the clutch and flywheel to provide rotation in the drive line between the engine for the vehicle and the transmission input shaft. A conventional clutch assembly incorporating a vibration damper comprises a hub having a barrel operatively connected to the transmission input shaft and an integral radial flange, a clutch plate carrying the friction facings and a spring retainer plate secured together in spaced relation on the opposite sides of the hub flange, and damper springs received in axially aligned sets of spring windows formed in the clutch plate, hub flange and spring retainer plate. Stop pins connect the clutch plate and spring retainer plate together and are received in elongated notches in the flange periphery to allow limited lost motion between the plates and the flange.
The above described damper assembly will provide a substantially constant rate of energy dissipation, and friction washers may be located between the plates and the flange to provide friction damping in addition to the resilient damping. However, specialized problems occur in a vehicle drive line, such as gear rattle during idle, which will not be solved by a conventional damper. Such specialized conditions will necessitate some form of a multi-stage damper to overcome the problems inherent therein. The present invention relates to a multiple stage damper which will overcome specialized drive line problems.